Light-sensitive material and a proc



-sitive materials described above.

Patented Jan. 5, 1937 UNITED STATES LIGHT-SENSITIVE MATERIAL AND A PROC- ESS 0F PRODUCING PICTURES Gottlieb von Poser and Robert Franke, Wiesbaden, Germany, assignors to Kalle & Co. Aktiengesellschaft, Wiesbaden-Biebrich, Germany. a corporation of Germany No Drawing.

Application September 13, 1932,

Serial No. 633,016. In Germany September 21,

14 Claims. (Cl. 95-6) The present invention relates to light-sensitive material, capable of yielding positive pictures from a negative original and to a process of producing pictures therefrom.

One object of the present invention is lightsensitive materials which are prepared by applying silver salts in mixture with light-sensitive diazo compounds upon or in a suitable support. The light-sensitive materials thus obtained yield rather good silverpictures, after exposure to light, after-treatment with alkalies or the like and fixation. All silver salts which are watersoluble may be used for the present invention, as for instance, silver nitrate. As diazo compounds there may be used all such stable, light-sensitive diazo compounds. as yield, when exposed to light, decomposition products capable of exercizing a reducing-action on the exposed silver salt. Such di- 20 azo compounds are, for instance, amino diazo com pounds of the benzene or naphthalene series, which may be substituted in the nucleus or in the amino group, for instance, by alkyl, hydroxy groups, carboxy groups, sulfo groups, halogen or the like. The amino diazo compounds of the benzene series useful in the present invention are preferably obtained from amino compounds of the following general formula: R-NH2 wherein R stands for a benzeneor a naphthaleneradical being substituted in the nucleus by hydroxy, halogen, alkyl, oxalkyl, oxaryl, oxaralkyl. an amino group, a substituted amino group, a carboxy group or a sulfonic acid group. The diazo compounds may be used as such, or in the form of salts, such as, for instance, sulfates, chlorobenzene-sulfonates, or the like.

Another object of the present invention is the process of preparing pictures from the light-sen- The material is exposed to light under a design and thereby is obtained a positive picture from a negative design and vice versa. After exposure to light, the. picture is treated with alkali or substances having an alkaline action, such as, for instance, ammonia, soda, borax, sodium acetate or the like, alone or in mixture with one another, and then subjected to a washing or fixating process, for instance, with sodium thiosulfate, in order to remove the substances which have not reacted. The formation of the picture probably takes place in such a way,.that the light acts upon the diazo compound which is rather sensitive to light, whereby the latter yields a. decomposition prodnot. This product, which preferably has a reducing action, acts upon the silver salt with the formation of metallic silver, which action is completed by the subsequent treatment with a substance of alkaline action. The silver picture thus obtained is then fixed in the usual manner. The

new process has the rather important advantage that the silver picture is obtained at once after the exposure to light and that a separate development process, as is necessary in the usual photographic processes, is not required. A further advantage lies in the rapidity of the formation of the picture, caused by the great light-sensitiveness of the diazo compounds used. Because of this fact it is possible to use silver salts which are not very sensitive to light. Thus also silver compounds which are of small value for photographic purposes, such as silver nitrate, can be used in the present process.

The light-sensitive material can be prepared according to one of the methods usually employed in diazo type printing and in photography. It is possible, for instance, simply to apply an aqueous or an aqueous-alcoholic solution of the mixtures of diazo compounds and silver salts on a base, for instance, paper, gelatinized paper or a film from a cellulose derivative or cellulose hydrate; the preservatives known from the photoprinting industry, such as, for instance, metal salts, acids, dextrine, starch etc. may be added. The lightsensitive substances can also be applied on a base in a colloid, such as, for instance, gelatine, in a manner customary in the photographic industry.

The proportion of the diazo salts and silver salts may vary within wide limits. According to the quantities of the two constituents, the kind of the diazo compounds, the silver salts and the substances added to the layer, and according to the after-treatment with alkaline agents, the tones vary from brown to black, and the gradation of the pictures varies, too. Other light-sensitive substancesfsuch as, for instance, ferric ammonium citrate, may be mixed with the layers, whereby more dark brown picturesare obtained. Ferric ammonium citrate has already been used together with silver salts for the preparation of light-sensitive layers, but when using the same quantities of silver, there cannot be obtained such rich and deep tones as according'to the present process.

The following examples illustrate the invention.

(1) 10 parts of the chlorobenzenesulfonate of the diazotized 1-amino-4-diethy1aminobenzene- Z-carboxylic acid ooon and 8 parts of silver nitrate are dissolved, while adding 4 parts of tartaric acid, in 250 parts of water. The solution is applied on photographic crude paper. On exposure to light under a negative design, a red picture is obtained which is already well visible. After bathing for a short time in a solution of sodium carbonate of 1% strength, the color of the picture turns to black. It is fixed for 1 minute in a solution of 4% strength of thiosulfate and washed with water. By addition of 5 parts of gelatine, pictures of a steeper gradation are obtained. Instead of the 1-diazo-4-diethylaminobenzene-2-carboxylic acid there may also be used with the same effect the corresponding sulfonic acid. Instead of paper, there may, of course, also be used other bases, such as, for instance, a film.

(2) 10 parts of 4-diazodiphenylaminesulfate obtained by diazotizing aminodiphenylamine of the following formula in a sulfuric acid solution, and 12 parts of silver nitrate are dissolved in 350 parts of water. The papers to which this solution is applied are exposed to light, treated with a solution of 3% strength of borax and fixed with a solution of 4% strength of thiosulfate. When using ordinary paper, yellowish-brown to brown pictures are obtained, and when using baryta paper, strong black pictures are obtained. Instead of 4-diazodiphenylaminesulfate there maybe used a corresponding quantity of the diazo compound of 1-amino-4-ethylaminonaphthalene.

(3) 10 parts of the chlorobenzenesulfonic acid compound of para-phenylenediamine of the following formula one amino group of which is diazotized in a sulfuric acid solution, are dissolved together with 6 parts 01' silver nitrate in 400 parts of water.-

When this solution is applied on paper, the latter yields, on exposure to light and after a treatment with sodium carbonate, pure brown pictures.

(4) 10 parts of the chlorobenzenesulfonate of the diazo compound of para-aminophenol (5) 15 parts of ortho-dimethylaminoaniline on, -N

are diazotized in a sulfuric acid solution. After neutralization of the acid, the solution is mixed with 12 parts of silver nitrate, and applied on paper. After exposure to light and a short treatment with a solution of 1% strength of sodium carbonate, yellowish-brown pictures are obtained.

We claim:

1. Lightsensitive material sensitized by means of a mixture of a water-soluble silver salt and a light-sensitive aromatic amino diazo compound of the benzene .series, the silver salt being used in sufiicient quantity to produce a silver picture.

2. Light-sensitive material sensitized by means of a mixture of silver nitrate and l-diazo-4-diethylaminobenzene-2-carboxylic acid.

3. Light-sensitive material sensitized by means of a mixture of silver nitrate and 4-diazodiphenylamine.

4. Light-sensitive material sensitized by means of a mixture of silver nitrate and 1-diazo-4- aminobenzene.

5. A process of preparing positive pictures from a negative design, which comprises exposing to light under the design a light-sensitive material sensitized by means of a mixture of a water-soluble silver salt and a light-sensitive aromatic amino diazo compound of the benzene series, the

silver salt being used in sufficient quantity to produce a silver picture, subjecting the picture thus obtained to the action of a. substance of alkaline acticnand then toa fixing process.

6. A process of preparing positive pictures from a negative design, which comprises exposing to light under the design a light-sensitive material sensitized by means of a mixture of silver nitrate and 1-diazo-4-diethylaminobenzene-2-carboxylic acid, subjecting the picture thus obtained to the action of a substance of alkaline action and then to a fixing process.

7. A process of preparing positive pictures from a negative design, which comprises exposing to light under the design a light-sensitive material sensitized by means of a mixture of silver nitrate and 4-diazodiphenylamine, subjecting the picture thus obtained to the action of a substance of alkaline action and then to a fixing process.

8. A process of preparing positive pictures from a negative design, which comprises exposing to light under the design a light-sensitive material sensitized by means of a mixture of silver nitrate and 1-diazo-4-aminobenzene, subjecting the picture thus obtained to the action of a substance of alkaline action and then to a fixing process.

9. Light-sensitive material sensitized by means of a water-soluble silver salt and a light-sensitive aromatic diazo compound, the light decomposition products of which have reducing properties for the exposed silver salt, the silver salt being used in sufiicient quantity to produce a silver picture.

10. Light-sensitive material sensitized by means of a. water-soluble silver salt and a light-sensitive aromatic diazo compound, which is substituted in the para-position to the diazo group by an amino group, the silver salt being used in sufiicient quantity to produce a silver picture.

11. A process of preparing positive pictures from a negative design, which comprises exposing to )ight under the design a light-sensitive material sensitized by means of a mixture of a watersoluble silver salt and a light-sensitive aromatic diazo compound, the light decomposition products of which have reducing properties for the exposed silver salt, the silver salt being used in sufficient quantity to produce a silver picture, and subjecting the picture thus obtained to the action of a substance of alkaline action and then to a fixing process.

12. A process of preparing positive pictures from a negative design, which comprises exposing to .light under the design a light-sensitive rnaterial sensitized. by means of a water-soluble silver salt and a light-sensitive aromatic diazo compound, which is substituted in the para-position to the diazo group by an amino group, the silver salt being used in sufficient quantity to produce a silver picture, and subjecting the picture thus obtained to the action of a substance of alkaline action and then to a' fixing process.

13. Light-sensitive material sensitized by means of a water-soluble silver salt and a light-sensitive diazo compound of the benzene series conforming to the following structural formula:

wherein X stands fora diazo group, Y stands for a member of the group consisting of hydrogen and an alkyl-amino group, and Z stands for a member of the group consisting of hydrogen, hydroxy, amino, alkyl-amino,andaryl-aminoof the benzene series, only one of the substituents Z and Y standing for hydrogen, the silver salt being used in sufficient quantity to produce a silver picture.

14. A process of preparing positive pictures from a negative design, which comprises exposing to light under the design, a light-sensitive material sensitized by means of a water-soluble silver salt and a light-sensitive diazo compound of the benzene series conforming to the following structural formula:

z g x wherein X stands for a diazo group, Y stands for a, member of the group consisting of hydrogen and an alkyl-amino group, and Z stands for a member of the group consisting of hydrogen, hy droxy, amino, alkyl-amino, and aryl-amino of the benzene series, only one of the substituents Z and Y standing for hydrogen, the silver salt being used in sufficient quantity to produce a silver picture and subjecting the picture, thus obtained, to the action of a substance of alkaline action and, then, to a fixing process.

GOT'I'LIEB VON POSER. ROBERT FRANKE. 

